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Michael Kuhne, D86NT: 12 GHz LO

Engllsh

Introduction

This microwave 1.0 is a new vcsrion of the LO describcd in DUDUŚ 4/1990. One can utilisc this module <łs a LO for 24 and 47 GHztransvcrtcrs as wclI as a generał LO-module tor the rmlliraetcr bands above 145 GHz. This module can be fur-nished wilh different crystals allowing for outpul frequencies between 11.7 and 12.1 GHz. It achieves an output power in excess of 35 mW.

Description

The crystal oscillator is contlgurcd as the wcll proven butler Circuit. The crystal itself is stabliscd by a heating element of Murata. The Circuit is compensated with a N470cnp(T8/15pf). This has possibly to be. adjusted to the crystal temperaturę characteristic.

In case of deraand for a very high stabllity an oven oscillator has to be configured. A circuit by DF9LN hastumed outtobevery useful albeitquiic siraplc. U can be. fedin by theextcrnal input jackct.

The oscillator shown can l>c tuned via a Hi-O TRONSER trimmer. The butler circuit is followcd hy a iwo stage FET*buffer, a tripler to 375 MH/. a helix filter, a doublcr to 751 MHz. a helix filier, a secortd doubler to 1503 MHz and a further heiix filter on 1503 MHz.

A doubler to 3 GHz is followcd by stnpłine filter. FETs t8 and T10 multiply the 3 GHz signal to 12 GHz. Tli and7 12 aniplify the quadrupied signal to 40 mW.

Constructlon

A PT1^:E board in SMD-teehniquc carrics the i cuit. li has lo shielded by a tmplate box. Total current is about 250 mA. Cooling is reąuired.

1.    Cut, drill and pul contnct throughs on the PCD

2.    Prepare tinpiąte box

3.    Mount FT and SM A-conncctor

4.    SolderinPCB

5.    Mount all SMD-parts to PGB

6.    Mount 7806 and 7809 to PCB and solder cooling fan to box

7.    Mount TAZ and eleos

8.    Mount TRONSER. the crystal and the heater

LO!2: Bottom Vlew

DUBUS 2/1996 12